Controlled engineering of spin polarized transport properties in a zigzag graphene nanojunction

TL;DR

This paper demonstrates that embedding cavities of various sizes in zigzag graphene nanoribbons can effectively control spin polarized transport and induce metal-insulator transitions, offering a new approach for spintronic device engineering.

Contribution

It introduces a novel cavity-based method to manipulate spin transport in graphene nanoribbons, supplementing traditional spin-orbit coupling tuning techniques.

Findings

Cavities of different radii can modulate spin polarization effectively.

Presence of cavities induces a metal-insulator transition without spin-orbit interaction.

Interplay between cavity dimensions and Rashba interaction influences transport properties.

Abstract

We investigate a novel way to manipulate the spin polarized transmission in a two terminal zigzag graphene nanoribbon in presence of Rashba spin-orbit (SO) interaction with circular shaped cavity engraved into it. A usual technique to control the spin polarized transport behaviour of a nanoribbon can be achieved by tuning the strength of the SO coupling, while we show that an efficient engineering of the spin polarized transport properties can also be done via cavities of different radii engraved in the nanoribbon. Simplicity of the technique in creating such cavities in the experiments renders an additional handle to explore transport properties as a function of the location of the cavity in the nanoribbon. Further, a systematic assessment of the interplay of the Rashba interaction and the dimensions of the nanoribbon is presented. These results should provide useful input to the spintronic behaviour of such devices. In addition to the spin polarization, we have also included an interesting discussion on the charge transmission properties of the nanoribbon, where, in absence of any SO interaction a metal-insulator transition induced by the presence of a cavity is observed.